Mixing two kinds of RAM

[Babrbarossa]

Hi- I have sitting here in front of me: two 1GB sticks of Buffalo Firestix pc-6400 4-4-4-9- 2.1V, and two 1GB stick of Crucial Ballistix pc-8000 5-5-5-15- 2.2V.

I'm trying to figure out a way to get all four to boot in my 680i, but am having no luck- it won't post at all. I've tried starting with each kind, setting them to ddr2-800 with relaxed timings, tried 667, and tried a few volatges before adding the second pair and rebooting. I know that you guys at TechGage have played with alot of memory sticks- especially Rob, so I was wondering if you had any suggestions. I know they're both micron D9s, but I'm wondering if the fact that the ballistix are EPP is what's causing the problems.

Also wondering if anyone knew how many layers the pcb on the ballistix is?

Thanks!

 

[Rob Williams]

I would reset your BIOS before installing the memory. If you can't boot, just use one stick of memory to get into your BIOS and reset it entirely, or just manually change all the memory related options back to auto.

-If- all goes according to plan, when you boot up, all four sticks should be set to the lowest available speed according to the SPD on the PC2-6400 kit. If you can't boot at normal speeds, just make sure that your CPC is set to 2T and not 1T.

If nothing seems to help, it could be that the ram simply won't cooperate. It would be odd though, as I believe both of those kits use the exact same chips. I really doubt Crucial would have thrown GKX into their then-highest placed part.

The Ballistix PCB consists of 6 layers.

 

[Babrbarossa]

Thanks for the quick reply, Rob- I went and tried what you suggested and a dozen other things and still no luck. I am anble to bott with one stick of buffalo together with one stick of crucial- so I'm suspecting that it might just be my first bad experience at the hands of a 680i, rather than a memory problem.

 

[Rob Williams]

Did you check the SPD for both the Ballistix and Buffalo and see if the lowest entry is vastly different? From what I recall, Ballistix PC2-8000 memory will have 400MHz 4-4-4 as the lowest SPD, which means the Buffalo might be trying to push the same. If that kit can't handle those speeds, it might explain why.

Do you know for sure what chips the Buffalo kit uses?

 

[Babrbarossa]

The Firestix are 6 layer too (I got that straight from the buffalo design engineer)

It's odd- the buffalo seems to want to default to ddr2-667 (I've read that those GMH chips are originally designed for ddr2-667) so I've tried starting them up that way, but I've also tried ddr2-800 with 5-5-5-15, 5-5-5-12, and 5-5-5-18. I've also tried using the crucial in the first slots, defaulting them, then adding one and two firestix, alternatively- and every combination of that nature (a firestix with a ballistix first, then another firestix, and vice versa- you get the picture).

The Crucial defaults to ddr2-800 5-5-5-18

 

[Rob Williams]

GMH are 333MHz chips, but that doesn't really matter. It depends on the company and what they decide to bin them at. 333MHz is just the official stock speed that comes out of Micron.

My 4GB Super Talent 6400 kit does the same thing though... defaults to DDR2-667 for some reason. But, when I paired up that kit alongside Mushkins 4GB 8500 kit, all four sticks defaulted to the DDR2-667 speed, which I was hoping would be the same scenario for you.

Crucial's PCB is completely custom from what I understand, so though both are 6-layer, they probably had different engineers. I really wish I could help, it just seems like those sticks do not want to work together at all.

 

[Babrbarossa]

Thanks Rob- If I figure anything out, I'll post an update.

 

[drewd]

Look along the short edge of the Crucial module and see if you can find either a four digit number that starts with a zero or a three digit number that does not. Post it here and perhaps I can help you out.

 

[Babrbarossa]

One module has 70201P levin on the pcb, and the other has 65001P levin.

The batch # i s CL1117M.QB
PN 72598
kit no BL12864AA1005.16FD3

I think I know what the problem is. The Firestix are binned as pc-5300!!- it allows for default settings of 200, 266, and 333MHz. (I know this isn't earth shattering news, but the Ballistix are default pc-8000 and only allow for defaults of 400 and 500MHz. Perhaps because they don't share a default speed, tehy can't work together.

I tried something that i had high hopes for- I put in both sets of modules separately and recorded ALL the timings when set at 400MHz with the timings set to Auto- even the minor ones down below, and then I put in the Firestix (because they wanted to default to 667) and manually set them to 800MHz with the default timings for the Ballistix and restarted- still nothing, dammit!

I don't know- maybe it's not possible to do with RAM that won't default to the same speed.

 

[drewd]

Ideally, the BIOS will look at the SPD and configure the system for the slowest memory speed. The Ballistix modules _should_ run at the slower speeds of the Firestix, but it's possible that the table doesn't have those speed grades programmed. If that's the case, then you'll have to set the frequency manually in your BIOS.

There is another issue that you may be facing and that is one of the loading of the chipset's address drivers. I can't speak to the performance of the Firestix modules in a 2 module per channel configuration, but the Ballistix modules will run at DDR2-800 with 2T command and address (with two modules in one channel). They may also run at 1T, but that depends upon the chipset in your system. They were designed with 1T operation in mind, but at higher speeds, sometimes it's a crapshoot to get that to happen.

My suggestion would be to manually set the memory clock to the lowest speed and slackest timings that you can, then try all four modules, making sure that each pair is in the same memory channel. If you're able to get everything to work, then start turning the speed up. Also, check your motherboard manual and make sure that the configuration that you're trying to use is valid, particularly at the memory speed that you're targeting.

I suspect that the Firestix modules are the weak link here - if they're rated at 667, bumping them up a whole speed grade with both modules in the same channel is a pretty formidable task.

 

[Babrbarossa]

Thanks!!- will try that out right now (not sure what you meant buy 'the loading of teh chipset drivers', but, I'll look around to see if I can figure that part out)- just FYI- when using just a pair- the firestix seem to be performing better than the ballistix - haven't tried may speeds over 1050, but at around 900, the firestix work with tighter timings and lower voltage than the ballistix. (preliminary though)

 

[drewd]

When I say "loading", I mean that when you put two modules in a single channel, the address drivers in the chipsets have to drive a total of 32 "loads" (each memory device represents a "load" on the driver). The address driver sees the chips as little capacitors - 32 of them. So, based on a little electronic math, the nice square wave that the driver puts out ends up looking a little like a sine wave (or worse) by the time it gets to the memory devices. That's because of something called an RC time constant. It's just a measure of how long it takes for an electrical pulse to charge a capacitor. More capacitors means more time, which means that the square wave doesn't look so square anymore. And the more that it deviates from being a square wave, the lower the performance of the module.

In simulation, the Ballistix modules are screamers. They're only limited by the performance of the chips themselves. That part, I have nothing to do with, but I know that the PCB was designed to go very, very fast.

 

[Babrbarossa]

Thanks again (are you a rocket surgeon? ) The Ballistix pcbs certainly look like better quality- I'm running them right now at ddr2 1150 5-5-5-12, 2.3V- going for higher soon.

Well I tried this, which is what I think you were suggesting:

--I put in the firestix and reset the bios to defaults (I did firestix first because the default is 667, so I figured if I manually set it to something the Ballistix could live with, I might be good)
--I set the mem voltage to 2.2
--the timings, i set to 5-5-5-18 and 3-30-5-9-7.8 all manually
--I had to unlink the memory because the CPU was at default- I set the mem to ddr2-800
--I set it to 1T
--I saved it all then shut down to put in the ballistix
--restarted, but no go

 

[Babrbarossa]

I have heard in the past from a couple of people that when running two sticks of ram on this board always put them in slots 0 and 1 so I didn't bother to try two sticks in slots 2 and 3....but on reading the manual (I know, I know rtfm ) , I discovered that you can put them either in 0,1 or 2,3- so I tried it tonight, and slots 2 and 3 DONT WORK FFS!! So thanks for your help, sorry for wasting your time- hopefully this thread will help someone out with a non-mechanical RAM problem. Now I have to decide whether it's worth an RMA.

 

[drewd]

Live and learn!

At least now you know what the problem is!